1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. In addition, the present invention relates to a machine, a process, manufacture, or a composition of matter. In particular, the present invention relates to, for example, a semiconductor, a semiconductor device, a memory device, a processor, a display device, a light-emitting device, a lighting device, or a power storage device. Alternatively, the present invention relates to a method for manufacturing a semiconductor, a semiconductor device, a memory device, a processor, a display device, a light emitting device, a lighting device, or a power storage device. Alternatively, the present invention relates to a method for driving a semiconductor device, a memory device, a processor, a display device, a light emitting device, a lighting device, or a power storage device.
The semiconductor device in this specification indicates all the devices that can operate by utilizing semiconductor characteristics. Note that a semiconductor device means a circuit having a semiconductor element (e.g., a transistor or a diode) and a device having the circuit, and the like. For example, an electronic circuit and a chip including an electronic circuit are all semiconductor devices. A memory device, a display device, a light emitting device, a lighting device, an electro-optical device, an electronic device, and the like include a semiconductor device in some cases.
2. Description of the Related Art
Much attention is focused on a semiconductor device that can retain data even after the interruption of power supply by using a combination of a transistor including semiconductor silicon (Si) in a region where a channel is formed (also referred to as a channel formation region) (this transistor is referred to as a Si transistor in the following description) and a transistor including an oxide semiconductor (preferably an oxide including In, Ga, and Zn) in its channel formation region (see Patent Document 1). A Si transistor is used in a variety of electronic circuits or electronic components. As a structural unit, an electronic circuit contains a cell (also referred to as a logic cell or a standard cell) such as an inverter circuit, a NAND circuit, and a flip-flop which are formed by arranging and wiring an n-channel Si transistor and a p-channel Si transistor (see Non-Patent Document 1).
On the other hand, transistors including an oxide semiconductor (preferably an oxide including In, Ga, and Zn) in their channel formation regions are known. It is known that a transistor including an oxide semiconductor in a channel formation region has extremely small off-state current because an oxide semiconductor has a wider band gap than silicon. For example, Patent Document 1 discloses a semiconductor device that can retain data even after interruption of power supply with use of such a transistor in a memory cell.
In recent years, demand for a circuit in which semiconductor elements such as a miniaturized transistor are integrated with high density has risen with increased performance and reductions in the size and weight of an electronic device.